1. Field of the Invention
The present invention is related to electrical connectors and terminals and, more particularly, is directed towards a terminal for insulated wire which is particularly designed to be connected through a circuit board.
2. Description of the Prior Art
It is frequently necessary to be able to quickly and easily terminate an insulated wire to a circuit board. To facilitate mass production, electrical terminals or connectors have been developed which are designed to protrude through an aperture in the circuit board, one side of the terminal being designed to be connected to the insulated wire while the other end of the terminal on the other side of the board may be connected to other circuit components. One effective known technique for quickly effecting a connection of the second end of the connector is by wave soldering.
I am aware of several prior art patents which teach various electrical connectors and terminals. These include: U.S. Pat. Nos. 3,072,880; 3,077,027; 3,504,328; 3,631,373; 3,780,211; 3,786,402; 3,808,588; and 3,880,488.
Exemplary of the foregoing is U.S. Pat. No. 3,786,402 which teaches an electrical terminal comprising a U-shaped sheet metal body and which is particularly adapted to protrude through an aperture in a printed circuit board. The insulated wire must initially be stripped and then wrapped about the upper portion of the terminal. While this procedure may be used with some types of insulated wire, it is extremely difficult to accomplish with several types of insulated wires which cannot be effectively stripped and/or soldered. Such types of wire include tinsel wire which is a combination of fibers and metal ribbons, and fine gauge stranded wire which is frequently provided with a tough, abrasion-resistant insulation.
U.S. Pat. No. 3,780,211 also teaches a connection member for a printed circuit board wherein the wire conductor is soldered into a cylindrical cup on one side of the board. Again, the conductor wire must be stripped prior to insertion into the cup, which is difficult for the type of stranded wire mentioned above. Additionally, tinsel wire cannot be soldered effectively. While fine stranded wire can be soldered, attempts to remove the insulation thereof is likely to result in damage to the strands, making this structure suspect for assembly on a mass production basis.
U.S. Pat. No. 3,808,588 illustrates another approach wherein a multi-strand wire is stripped and fastened to the connector. The strands extend into the circuit board area on both sides of the board, which means that wave soldering of the protruding end of the terminal will solder both the terminal and the strands together. This creates obvious obstacles with respect to hard-to-solder tinsel wire, while fine stranded wire will encounter the same difficulties mentioned above with respect to Pat. No. 3,780,211.
The prior art terminal and connector designs also suffer from two additional major deficiencies. One disadvantage results from those terminals which place the insulation of the wire close to the circuit board. During wave soldering, the heat of the process can cause the insulation to melt and flow. If the insulation flows into the hole where the connector pin is inserted, the insulation can cause a bad solder connection around the pin.
A second major difficulty, which also results from melting of the insulation, is that the solder bath can become contaminated, which would result in costly down-time for the production line.
It is towards overcoming the above-mentioned deficiencies that the present invention is advanced.